The present invention relates generally to security systems to provide security for a protected function and, more particularly, to a security system that uses a challenge/response protocol to provide security for the protected functions.
Traditional locks employ a key or combination to limit access to property. Presumably, only persons with right to access the property will possess the key or combination needed to operate the lock. This traditional approach is still widely used. More recently, traditional key and combination locks have been replaced by electronic locking systems actuated by plastic cards with magnetic strips. This type of electronic lock is commonly used in hotels. In this type of system, a door handle and electromechanical locking mechanism are integrated with a magnetic card reader within a strong metal enclosure. The magnetic card reader reads the inserted card, checks for a key code, and actuates the locking mechanism to unlock the door if the correct key code is supplied.
It is also known in the past to use some sort of identification, such as a PIN code, fingerprint, or iris scan, to enable a locking mechanism to unlock a door. One such device is disclosed in U.S. Pat. No. 6,038,666 to Hsu et al. This patent discloses a wireless method of operating a door lock using fingerprint data. The door lock must first be loaded with fingerprint data of an authorized user and the user's public cipher key. A mobile device carried by the authorized user is also loaded with the same fingerprint data and communicates wirelessly with the door lock. The name of the user is transmitted unencrypted to the door lock. The door lock generates a random public/private cipher key pair and sends the public key to the user's device. The user's device doubly encrypts the fingerprint data using the user device's private key and the door lock's public key in unspecified order, and transmits the result to the door. The door decrypts the received fingerprint data and compares it with the stored fingerprint data, unlocking the door if the fingerprint data matches.